"When you come down to it, you can't go wrong with a badger with guns."

There's an argument to be made for saying that Bryan Talbot is the most important comic creator in Great Britain. It's difficult to think of another who has done so much for so long and in so many different areas. From his days as an underground cartoonist he progressed to working on Judge Dredd and Batman. But this century he has been responsible for some of the finest examples of the graphic novel form, both on his own and in collaboration with his wife Mary Talbot. Earlier this year the couple published Sally Heathcote, Suffragette (with finished art from Kate Charlesworth), while their first book together, Dotter of Her Father's Eyes, won the Costa Prize for biography in 2012.

Talbot himself is responsible for The Tale of One Bad Rat (which draws on the influence of Beatrix Potter) and the very fine psychogeographical history, Alice in Sunderland. But here he talks about his anthropomorphic alternative history series Grandville with its badger hero Inspector LeBrock. The latest volume, the fourth, Grandville Noel, (Jonathan Cape, £16.99) is available now.

How did the idea for the Grandville series originate?

My graphic novels always take months, often years, to gestate: a long process of mulling over, note-taking and research. The first Grandville story was the one dramatic exception. Shortly after finishing Alice in Sunderland, I was browsing through a book I've had for decades, on the work of Jean Ignace Isidore Gérard, a French illustrator and cartoonist who lived in the first half of the 19th century. He did many drawings of anthropomorphic characters in the then contemporary dress of the time, satirising the French social mores of the day and was, incidentally, a big influence on John Tenniel, who produced the original illustrations to Lewis Carroll's two Alice books. He signed his illustrations with his nom-de-plume: "JJ Grandville". Looking through the book, it suddenly occurred to me that "Grandville" could be the nickname for Paris in an alternative reality where it was the biggest city in a world populated by talking animals. Aside from a small section of The Tale of One Bad Rat, I'd never done an anthropomorphic story before and, I thought, never done a detective story as such (despite a liking for crime fiction). This sparked an intense creative rush in which, over the following week, the story seemed to come to me fully-formed. I scribbled a quick plot structure, completely dispensed with my usual method of first doing the book in rough thumbnail sketches to visualise the pages, and went straight to the computer. I typed the script for the whole book straight out in the next five or six days. It was like taking dictation: I knew exactly what should happen in each scene and the characters seemed to come up with their own dialogue spontaneously. It's never happened to me like that since, but I wish it did. Though, after that book, I now always dispense with the rough sketch stage and go straight to script, just visualising each page in my head as I go . Of course, I polished the script as drew it, as I usually do, over the year that it took to draw it, but it was mostly very close to the original draft.

What's the appeal of anthropomorphism (and why is your hero a badger)?

Ascribing human characteristics to animals (and even inanimate objects) is something that everybody does and, for some reason, we enjoy images and stories featuring humanised animals. Anthropomorphic or, strictly speaking, zoomorphic characters have been around for as long as people have told stories. They can be seen in neolithic cave paintings and early carved figures. The so-called Lion Man (it's arguably a woman), a human figure with a lion's head, carved from a mammoth tusk and discovered in the Stadel caves in Germany, is over 30,000 years old. All the world's mythologies and religions contain anthropomorphic characters, from the entire Egyptian pantheon to the serpent in the first book of the Bible. Aesop, though, whose fables were written in the sixth century BC, must surely be considered the godfather of the Western modern anthropomorphic story - though they've existed continually in folklore and fairy tales all over the world. But, to put it in a nutshell, I've no idea what the appeal of anthropomorphism is!

There are several reasons why I chose a badger for my detective protagonist. Firstly, because they look great - something to do with the black and white colouration that gives the impression of a mask - and, to my infant mind, Bill the badger was always Rupert Bear's coolest friend, probably for this reason. The love interest in Grandville, Billie, the prostitute badger, is named after him. As for LeBrock, I wanted a character who was tenacious and who could be ferocious, and that's badgers for you. As well as having the deductive abilities of Sherlock Holmes, Detective Inspector LeBrock is also quite happy to use extreme force when needed. Badgers are often portrayed in children's stories as being working class, perhaps something to do with them living underground, and I wanted to use that aspect too. LeBrock isn't a toff in a class-ridden society - something I go into a little more in the fifth book, which I scripted over two years ago.

The Wind in the Willows was a favourite story of mine and Badger is by far the most capable and decisive character in it. That book is partly where Detective Sergeant Roderick Ratzi comes from too - well, that, Lord Peter Wimsey and Bertie Wooster. It's definitely where the toad villain, Baron Aristotle Krapaud in Grandville: Bête Noire, originates. His stronghold is even called Toad Hall. Basically, though, when you come down to it, you can't go wrong with a badger with guns.

At what point does research end and imagination begin?

I do a lot of research to get the Parisian atmosphere right. I've snapped locations in Paris and accumulated books containing photographs and illustrations of the city in the 19th Century. I have a huge collection of references - pictures of old machinery, furniture, artefacts of all sorts - to create the steampunk feel. I've visited places such as the Institute of Science and Technology in Manchester and the Think Tank Science Museum in Birmingham to photograph 19th century steam-powered machines, and places like police museums and Victorian factories. I've also been to the Natural History Museums of Helsinki, Milan and Dublin to photograph their extensive collections of stuffed animals. The imagination comes in incorporating and adapting this raw visual material into stories, inventing machines based on old technology, and giving human expression to the animals. The stories, of course, are all set in a world of my own making, not in the actual Belle Epoch, so I've free reign to invent, as long as it works.

Grandville Noel is your take on religious conspiracies? Why are so many drawn to the conspiracy theory?

I can't speak for anybody else but, for me, it all came out of imagining the world of Grandville and trying to envisage different aspects of it, such as - how on earth did these anthropomorphic creatures evolve? How would their religions differ from ours? The latter lead directly to me thinking about their Bible and I realised that they would have a different book of Genesis. I think that the concept of Noah being acclaimed as their creator made sense: "In the beginning was the water … " and Noah arrives from heaven, in the ark with all the animals. It also got me thinking "what species was Jesus in their world?" That seemed to me like the fine makings of a religious conspiracy story which I could weave into a tale that was already dealing with a messianic unicorn, an unorthodox religious cult and set at Christmas. I even partly explain their evolution.

All your work is in love with literature. Your stories are nested into other people's stories. Why does story matter so much to you? And to everyone else?

Stories seem to be a fundamental necessity for human beings. If not in prose fiction, then in movies or plays, comics, video games, religious texts, mime, even in the form of simple jokes or anecdotes about our lives or people we may or may not know, and real or imagined events. Stories of the hunt were painted on the walls of caves. And, as with the appeal of anthropomorphic animals, I've absolutely no idea why we love them. I suppose they both entertain and educate. In a story, we can experience other realities, other times, other people vicariously. I'm sure everybody knows this already, so I'll stop digging now.